XP installation problem

THIS IS A LONG AND SAD STORY, ANY ADVICE MOST WELCOME: About 18 months ago i built a socket 754 barebones PC for my son. After a while it kept shutting down for no reason at all, so after various attempts to sort it out I decided to reinstall my copy of Windows XP home (with SP2). This seemed to make the problem worse, and after exhausting all the options I decided that it was a hardware problem, so about 6 months ago bought a new motherboard. No improvement, so I decided to buy a new hard drive this time. By this time another problem seem to arise, which is what I want help with now. Every time I use the XP installation disk to install a new copy on the (deleted partition) hard drive, it gets stuck copying certain files over from the CD to the HD, but it seemed to be the same files each time. I tried installing without these files (about 10 in all), but I was left with a host of operating problems. At this point I thought it was a problem with the CD itself, because it looked scratched. I tried various recommended methods to 'clean' it (toothpaste, brasso etc.!!), but to no avail ultimately. So finally I decided to buy a new installation CD, which I received today: and STILL THE SAME PROBLEM!! There is much more I could add. But I really am at the end of my tether. Is there anything else I should try?

Are you ABSOLUTLY sure you have a genuine XP cd and product key. I know a 'friend' who tried to install the same copy of XP onto a second machine and after the product key was entered, it left out some key files. This stops the operating system starting and therefore stops you using an illegal copy.

yes it won't install the files in the setup process, before anything like WGA kicks in (though it does resemble the previous posting). Having said this, I've tried numerous times to install XP on the drive, which kinda worked first time, so maybe something is 'on' the drive already affecting future installations? (despite deleting the drive partition in setup, there is an extra 8MB left 'outside' the partition when I get to deleting the partion on starting installation, is there anyway of 'completely' deleting the drive?, or should I jsut clear CMOS?). But yes it is a SATA drive (though I had the same problem with an IDE drive previously), and XP does 'see' the drive, so I haven't bothered since the first few times to install the SATA drivers on F6 at startup. But I could try again, but suspect it will be the same result.